Rotational direction on treads?

BUICK

Hi. I picked up some Schwalbe Blizzard/Lugano Tyres at a cycle fair locally a week or so ago - when it came to fitting them I noticed that although there isn't an elaborate tread it definitely has a 'direction' as there are angled lines on the side, and there is no indication what direction they are intended to be on the bike on either the tires or the labelling that came with them. Riding a motorbike when I'm not cycling I know that it is considered to be pretty crucial that tires are on the right way around or they may not behave as intended and it could lead to an accident, so I put a search in on the internet and tried to find a definitive answer. The good news is I found one. The bad news is I found a lot more that contradicted that one and each other! Is there a sensible answer I've missed? I looked at the tire treads on the other bicycles in the house and none of them looked remotely the same so it didn't help. The answers I've seen so far are like this:
>>>>> >>>>>
<<<<< <<<<<
>>>>> <<<<<
<<<<< >>>>>
...reading left to right. In all cases there were arguments based on water clearance and stopping power and they all kind of sounded feasible... and one final answer that on road tires it just doesn't matter?! Any ideas? One last thing - there was a suggestion that you just put the logo on the drive side - these tires are labelled equally on both sides!

Thanks :shock:

Smokin Joe

Treads on road tyres are strictly for decoration only, they perform no function. The treads are not deep enough to channel water from under the tyre like they do on a car or a motorcycle and the tyre is narrow enough to cut through water anyway. It does not matter which way round you put them on.

BUICK

I can buy that it doesn't make a lot of practical difference - I guess maybe in extreme conditions, cornering fast is the only time it might have some small impact - but seeing as I ride fast and right through winter I would have liked to get it right! There must be a general reasoning to which way to go from an expert point of view?

Saturn

I'm don't know about Schwalbe but I enquired direct to Continental as I'd bought some new conti's that didn't have the direction arrow that my old ones had. Continental said that it didn't matter which way round any of their road tyres are fitted but for cosmetic purposes it is traditional to fit them <<<< >>>>> looked at from above

Im not sure about other manufacturers but I'd guess the same might be true about all road tyres but that possibly MTB tyres and maybe cylcocross tyres might have an optimal fitting direction.

meagain

SOME come with specific rotation, but I suspect more to do with drive/grip in mud and/or loose gravel type conditions - thus mostly on mtb tyres or "all terrain" touring tyres. When just shallow splines then I think more to do with determining safe wear limit than water shifting ( I once read that to aquaplane on a pedal two wheeler would need to travel at approx 220 mph!).

Also a PTW rider, I don't think need to judge cycle tyres in same way.

redddraggon

My road tyres don't even have any tread. So the direction they are fitted shouldn't matter even on ones with tread.

neeb

For MTB and heavily-treaded road/touring tyres, I've always assumed the following (based on something I read somewhere as well as the directions on some tyres I've had).

If there is a "V" trend to the tread, i.e. <<<<<<, it should have more grip (at least in mud) when sliding in the opposite direction to the way the Vs point, i.e. a <<<<< tread will grip more in the => direction. For the rear tyre traction is most important as the rear wheel is the drive wheel, so you want the Vs to be pointing forward when in contact with the ground. For the front tyre you want most grip in the opposite direction (i.e. forwards) as this is where most of the friction is generated when braking, so the Vs should point backwards.

I habitually mount any tyres that have any sort of "V" trend to the tread in this manner.

Lagavulin

I thought it was odd the Mondo Pros my bike came with stated quite clearly which way they should be mounted when there's not even the hint of a tread. :?:

neeb

Looking at Saturn's post, this is the same as the traditional method he mentions. If the treads are <<<< >>>> looking from above, then they are >>>> <<<< when in contact with the ground, i.e. looking from below.

BUICK

Thanks for the input. I did have the Mondos on this bike previously - it does seem daft for them to have direction of rotation arrows when they are completely slick!

JWSurrey

Interesting - I have some Conti tyres with rotation direction indicators on them.
I assumed it was perhaps something to do with the "canvas" weave directionality, rather than the rubber itself.
There was a post a few months back where the poster suggested, after their own experience, that the rotational direction made a difference to the handling, however as one of the above replies mention - they've contacted Conti, who say there is no difference!

The late Sheldon Brown did a calculation for aquaplaning on a bike tyre - I think the speed was somewhere around 200mph!